Electrical regulation



May 24, 1938.

F. J. CHAMPLIN ELECTRICAL REGULA'I' ION Original Filed May 14, 1935 Inventor m h Cam ra m MW Y Ream! May 24, 1938 20.134 auto-rare, REGULATION Franklin J. C-lmmplin, Dalton, Mass, assignor to General Electric Company, a corporation of New York Original No. 2,022,537, datedNovember 26, 1935,

. Serial No. 21,312, May 14, 1935.

Application for reissue November 26, 1937, Serial No. 176,701

11 Claims.

My invention relates to electrical regulation and more particularly to improvements in the control of electromag'netically operated contact closes a set of contacts and the efiect of the holding coils is to produce a bias in the meter tending to hold the contacts relatively firmly together so as to prevent chattering of the contacts.

In accordance with my invention, ,1 provide a novel and simple control arrangement for such contact making devices which permits the elimination of conventional holding coils. This result is accomplished by varying the energization of the main operating winding of the contact making device, whenever one orthe other of its contacts closes, in such a way as to produce an eii'ect which is the equivalent of the ordinary holding coil eflect.

Many regulators controlled by contact making voltmeters are operated by reversible electric motors. When there isno convenient auxiliary source of current supply for energizing. these motors it as been the practice to connect them to be energized by the same voltage or potential transformer from which the main operating winding of the contact making voltmeter is energized. Due, however, to the fact that the motor draws a relatively large current with respect to the current required by the contact making voltmeter, an ojectionable voltage drop, due to the motor current, is produced in the potential transformer and in order to eliminate the effect of this voltaged drop on'the contact making voltmeter various means such, for example, as an auxiliary solenoid winding on the contact making voltmeter or a so-called stabilizing transformer has been employed to eliminate this effect. A stabilizing transformer is. a small transformer which responds to the motor current and which induces in the contact making .voltmeter operating winding circuit a voltage which is equal and opposite to the voltage drop produced by the motor current in the potential transformer. Al.-

though my invention is not limited thereto, I find it convenient in certain instances to combine my means for producing an equivalent holding coil effect with a stabilizing transformer for in this way the number of separate parts required in the system is materially reduced.

An object of my invention is to provide a new and improved .system of control for electrical regulating systems.

- Another object of my invention is to provide an arrangement for eliminating holding coils on contact making voltmeters without otherwise changing their construction.

My invention will be better understood from the following description taken vin connection with theraccompanying drawing and its scope will be pointed out in the appended claims.

In the drawing, Fig. 1 illustrates diagrammatically an embodiment of my invention in which the means for producing the equivalent eifect of holding coilsis combined with the stabilizing transformer and produces this effect by varying the voltage applied to the main operating winding of the contact making voltmeter; Fig. 2 is a diagrammatic showing or a modification in which the means for producing the equivalent efiect of holding coils is separate from the stabilizing transformer and circulates an auxiliary current in the operating'winding of the contact making voltmeter; and Fig. 3 is a modification of Fig. 2 in which the auxiliary electric motor shown as a well known capacitor motor 3 having two directions of rotation controlling circuits 4 and 5 and'a return conductor 6.

The proper energization of the reversing circuits 4 and 5 is controlled by a contact making voltmeter 1 having a main operating winding 8 which operates, through the conventional solenoid core, a pivoted contact beam 9 having a set of raise contacts iii and a set of lower" contacts ii, respectively. The main operating winding 8 is connected to be responsive to the voltage of circuit l by means of a potential transformer i2 across which the winding 8 is connected through a conventional series resistor i3. The motor 3 is also connected to be energized by the potential I transformer l2. Thus the return conductor 6 is to the contact beam 9.

.Connected in the energizing circuit for the operating winding I and in the reversing circuits 4and I for the motor 2 is a special transformer l5 having a secondary winding it connected in circuit with operating winding l and having individual primary windings l1 and I8 connected respectively in the reversing circuits 4 and 5'.

The operation of Fig. 1 is as follows: The position of the parts represents a-normal voltage condition on circuit l. Assume now that for any reason the voltage of circuit l becomes too low and falls slightly below the normal value. Under these circumstances the energization of operating winding 8 is weakened thereby causing the solenoid core 8 to descend and resulting in the engagement of the raise contacts ID. A circuit is then completed from one side of the secondary winding of the potential transformer l2 through the conductor, raise contacts l0, primary winding ll on transformer l5, circuit 4 formotor 3' and back through the return circuit i to the other side of the potential transformer. These connections are such as to cause the motor I to turn the regulator 2 in a direction to raise the voltage of circuit I. The motor current flowing through the winding l1 induces avoltage in the secondary winding l6 and I make the relation between these windings such that this voltage which is induced in the winding I6 is opposite in direction to the voltage drop in the transformer I! caused by the motor current but which is less than equal to this drop by an amount which produces on the winding I the equivalent of the conventional holding coil effect. In other words the voltage drop in the transformer I2 is not quite,

compensated so that the contact making voltmeter acts as though the voltage of circuit i were slightly lower than it actually is. This, of course, causes the "raise" contacts II to be held in engagement .until the voltage of circuit I exceeds the ideal normal value by a slight amount. It will be seen that this is exactly the equivalent of the effect produced by a holding coil as the holding coil would tend to hold the contacts l0 together and thus would require a slight excess voltage applied to the winding I in order to cause the contacts to separate. This operation, like the conventional holding coil operatiom'has the advantage of tending to prevent chattering of the contacts. When the contacts ill do separate at a voltage slightly above normal the motor is deenergized, the voltage drop in the transformer 12 disappears and the compensating voltage produced by the transformer l5 disappears so that a very slight increase in voltage is applied to the operating winding 8. This helps to bring the contact beam up to its normal midposition, which This connection causes the motor I to operate in the reverse direction to cause the regulator 2 to lower the voltage of circuit I. tween the windings l8 and it of transformer II is such that the 'voltage induced in the winding i6 slightly overcompensates for the voltage drop in the transformer i2 produced by the motor current. Generally speaking, this overcompensa- The relation betion' is about asmuch as the undercompensation I produced by the primary winding ll. Thus there is applied to the winding 8 of the contact making voltmeter I, when the lower contacts are closed, a'

voltage which is slightly in excess of the voltage drop produced in the transformer l2. This ex-' cess serves to hold the lower contacts flrmly in engagement and produces an effect which corresponds to the ordinary holding coll effect. When the voltage of the circuit l falls slightly below the. average or ideal normal value this excessenergization of the winding 8 will be overcome and the contacts ll will separate thereby stopping the motor. The voltage drop in transformer l2 and the voltage induced in the winding I will then disappear and the contact making voltmeter will return to its balancedmidposition as shown .in the drawing.

winding of the contact making voltmeter, but

due to the slight over and under compensating holding coil effect producingvoltages in transformer l5 such a meter when connected in parallel with the winding 8 of Fig. 1 will not always read accurately. 5 However, in the modification shown in Fig.2 this difficulty is overcome by producing the holding coil effect by means of an auxiliary current which is circulated in the operating winding 4.

Fig. 2 differs from Fig. 1 inthe following particuiarsz'A conventional stabilizing transformer is is substituted for the special transformer Ii of Fig. l. Transformer I! has a secondary winding 2! connected in circuit with the operating winding 8 of the contact making voltmeter and has a primary winding 2] connected to carry the motor current whenever the motor is energized. This transformer is so designed as to produce a voltage in the contact making voltmeter energizing circuit which is equal and opposite to the voltage drop in the transformer l2 produced by the motor current. An auxiliary current transformer 22 also is provided. This transformer has a secondary winding 23 connected across the operating winding 8: of the contact making voltmeter and it has a pair of reversely acting primary windings 24 and 25 connected respectively in the reversing circuits 4 and S of the operating motor for the regulator. The remaining difference between the two figures is that a split fielcl' motor 26 is shown in Fig. 2in place of the capacitor motor 3 of Fig. 1.

The transformer 22 is so constructed that de .pending upon which of the reversing circuits 4 or .5 is energized relatively small reverse currents are induced in the secondary winding 28 and these currents are circulated in the winding '8 so as to add or subtractfrom the current in this winding produced by the voltage of circuit I.

This added or subtractedcurrent is suchas to produce the'proper equivalent holding coil effect. For example, if the voltage of circuit I is low and the ralse contacts ll close, the winding 24 of the transformer 22 is energized and this produces a current in the secondary winding 23 which is in such direction as to subtract from the current in the winding 8 thereby in effect reducing the total energization of this winding and the amount of this reduction is such as to produce an equivalent holding coil eflect. Likewise when the voltage circuit I is too high and the "lower contacts H close the primary winding 15 will be energized and will produce a reverse current in the secondary winding 23 which current will add to the current already in the winding 8 an auxiliary current of an amount sumclent to produce an equivalent holding coil effect so as to hold the contacts Ii firmly in engagement. As shown in the drawing, winding 23 is adjustable so that the amount of equivalent holding coil eifect can readily be adjusted.

Although in both Figs. 1 and 2, I have shown the contact making voltmeter contacts arranged to carry the motor current, it will of course be obvious to those skilled in the art that this is not necessary and if desired the usual and conventional auxiliary relay or relays may be interposed between the contact making'voltmeter contacts and the motor circuits. In that case the primary windings i1 and I8 of transformer l5 of Fig. l or the primary windings 2i and 25 of the auxiliary current transformer 22 of Fig. 2 may either be connected in the contact making voltmeter contact circuits or in the motor circuits. I prefer to connect them in the contact circuits because the unavoidabie time delay in the operation of the relaymight allow the contacts to reopen before the meter current starts In the modification shown in Fig.v 3 the auxiliary current produced by winding 23 is passed through a resistor 21 and the resultant voltage drop affects the energization of winding 8 in such a manner as to produce the desired equivalent holding coil eifect.

While I have shown and described particular embodiments of my invention, it will be obvious to those skilled in the art that changespnd modiiications may be made without departing from my invention, and I therefore aim in the appended claims to cover all such changes and modifications as fall within thetrue spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In combination, a contactmaking electroresponsive control device for a regulating system, and means responsive to the closing of the contacts of said device for varying its energization in a manner to produce an equivalent holding coil effect.

2. In combination, means having an operating condition to be regulated, means including a contact making device for regulating said condition, an operating winding for said device, and means including a transformer responsive to the closing of the contacts of said device for varying the energization of said operating. winding by an amount corresponding to a proper holding coil efl'ect.

3. In a voltage regulating system, in combinaw tion, an alternating current circuit, a potential transformer connected thereto, a contact making voltmeter having its operating winding connected to be energized by said transformer, a reversible alternatingcurrent motor having its direction of voltmeter havingan operating winding connected g to respond to the. voltage of said circuit, and a transformer connected to be energized when said contact making voltmeter closes its contacts for' producing a voltage change with respect to said operating winding which produces the equivalent of a proper holding coil effect.

5. In a voltage regulating system, in combination, an alternating current circuit, a potential transformer connected thereto, a-contact making voltmeter having a set of "raise contacts, a set of lower" contacts and an operating winding connected to be energized by said transformer so as to close the set of raise contacts when the voltage of said circuit is below a predetermined amount and to close said set of "lower" contacts when the voltage of said circuit is above a pre determined amount, a reversible motor having two circuits connectible selectively to said transformer by means of said "raise" and lower contacts, respectively, and a transformer having a secondary winding connected in circuit with said contact making voltmeter operating winding and having two primary windings connected respectively to respond to the contact current when said "raise and lower" contacts close, the primary winding which is energized when said raise". contacts close inducing a voltage in the said secondary winding which is less than the motor current produced voltage drop in said potential transformer by an amount corresponding to a desired holding coll effect, the other primary winding when it is energized inducing in said secondary winding a voltage which exceeds said voltage drop by an amount corresponding to a desired holding coil effect.

6. In a voltage regulating system, in combination, an electric circuit, a regulator controlling contact making voltmeter having an operating winding connected to respond to the voltage of said circuit. and a transformer connected to be energized when said contact making voltmeter closes its contacts for circulating in said operatingwinding an auxiliary current for producing an equivalent holding coil efiect.

'7. In a voltage regulating system, in combination, an alternating current circuit, a potential transformer connected thereto,,a contact making voltmeter havingtwo sets of contacts and an operating winding connected to be energized by said transformer so as selectively to close said sets of contacts depending upon whether the voltage of said circuit is too high or too low, a two circuit reversible regulator operating motor connected to be energized by said transformer and to have its direction of rotation controlling circuits selectively energized by the closure of said respective sets of contacts, a transformer connected tobe responsive to the current required by saidmotor for compensating said conthe motor current, and a current transformer having a secondary winding connected to said contact making voltmeter operating windingfand having two primary windings connected respectively in the contact circuits, the primary winding which is energized when the voltage is'too high inducing a current in the secondary winding which adds to the current in the contact makingvoltmeter operating winding an amount sufllcient to produce an equivalent holding coil effeet; the other primary winding when it is enersized-inducing a like current in the opposite direction in said secondary winding.

8. Ina voltage regulating system, in combination, an electric circuit, a regulator controlling contact making voltmeter having an operating winding connected to respond to the, voltage of said circuit, and a transformer connected to be energized when said contact making voltmeter closes its contacts for causing a voltage drop in the circuit of said operating winding for producing an equivalent holding coil eflect,

9 In combination, a contact-making voltmeter having a setof control contacts, auxiliary means having a winding whose energlzation is controlled I 20,7s4 drop in said potential transformer produced by former action from said winding for causing said contacts to be held firmly in engagement when said winding is energized.

10. In an automatic regulator system, a regulator of a variable quantity, a primary relay responsive to said quantity for controlling said regulator, and means energized by transformer action and controlled by said relay for holding the contacts of said relay in relatively firm engagement in response to the engagement of said contacts.

11. In a regulator system, a contact-making voltmeter having a normal position and a contact-making position, a source of current supply,

a winding connected in circuitwith said source of current supply and the contacts of said'contact-making voltmeter, a second winding inductively related to said first-mentionedwinding and adapted to be energized by transformer action from said first winding, and means energized by said, second winding for producing. a holding effect which tends to maintainfisaid contactmaking voltmeter in its contact-making position.

FRANKLIN J. CHAIMPLIN.

by said contacts, and means energized by trans- 

